Method and apparatus for mixing liquids



Mam]! 1944- A. DE v. HARNETT METHOD AND APPARATUS FOR MIXING LIQUIDS 3 Sheets-Sheet 1 Fil'ed July 20, 1940 U r I. 8 Q h a 9 2 J m m 5 m 4 C 210 5/ SOLUTION DAM mR M ACETATE AMV L w ACETATE UJYL M D W 4 G m S Szora ge Drum INVENTOR m m H mw v m 8 D As March 7, 1944- A. DE v. BARNETT 2,343, 54

METHOD AND APPARATUS FOR MIXING LIQUIDS Filed July 20, 1940 3 Sheets-Sheet 2 EYE Gear Box I 1 8 flgizgzzzng I I Gear 174 175%} Bar INVENTOR A. De Vere Harne Ti ATTORNEYS March 7, 1944.

A. DE v. HARNETT METHOD AND APPARATUS FOR MIXING LIQUIDS Filed July 20, 1940 3 Sheets-Sheet 3 TOLUOL arm ALCOHOU BUTYL (1/. CEIEUSOLVE BUTYL Storage Drum R0 Y E Patented Mar. 7, 1944- y L 1 UNITED STATES PATENT OFFICE I METHOD AND APPARATUS FOR MIXING LIQUIDS A. De Vere Barnett, Racine, Wis. Application July 20,1940, Serial No. 346,609

19 Claims. (01. 259-84) The present invention relates to improved apparatus and an improved method for mixing lacquers, paints, enamels, varnishes, liquors and the like, certain of the constituents of which are'extremely volatile and highly inflammable liquids'.

It is an object of the present invention to pro-, vide improved apparatus of the character described which is of simple arrangement and is easily controllable to produce any desired quantity of a product of the class described, the different batches of which may differ in character.

It is another object of the invention to provide apparatus of the character described which is arranged in an improved manner such that the liquids to be used in a particular batch of a, desired product may be transmitted to a common mixing chamber and the quantity of each liquid admitted to the mixing chamber accurately controlled and measured with a minimum of apparatus and a minimum number of control operations.

It is a further object of the invention to provide improved apparatus of the character described which is particularly adapted for use in a small mixing plant and is so arranged that the fire hazard attendant with the mixing of easily vaporized and highly inflammable liquids is reduced to aminimum. i

It is another object of the invention to provide improved apparatus of the character described which is so arranged that all of the parts are maintained at ground potential to preclude electrical discharges therebetween', and all of the liquid chambers, containers and conduits are effectively sealed to prevent the escape of inflammable vaporization products to the surrounding atmosphere.

- It is a still further and more specific object of the invention to provide improved apparatus of the character described wherein all of the chambers and containers to which thevolatile liquids are transmitted are, during use of the apparatus, partially exhausted to remove therefrom any vaporization products resulting from the transmission and mixing of the liquids.

It is another object of the invention to provide an improved method of mixing a product of the character described wherein large or small batches of a product having the same or different characteristics may be mixed as desired with a minimum amount of apparatus and a minimum number of steps.

It is a further object of the invention to provide an improved method of the character described wherein the steps are so arranged that the quantity of each liquid utilized in mixing a batch of a desired product may be accurately controlled and measured.

It is still another object of the invention to provide an improved method of the character described wherein the vaporization of the volatile liquids is reduced to a minimum andthe escape of vaporization products from the apparatus utilized in practicing the method is positively prevented.

It is a still further and more specific object of the invention to provide an improved method of mixing lacquers, paints, enamels and the like, wherein the steps are so arranged that the constituents of the desired product and the constituents of a thinner therefor may be mixed at the same time and with the same apparatus. V The novel features believed to be characteristic of the invention are set forth with particularity in the appended claims. The invention, both as to its organization and method of operation, together with further objects and advantages there of, will best be understood by reference to the specification taken in connectionwith the accompanying drawings in which Figures 1, 2 and 3, when placedvside by side in the order named, illustratepartiallyschematically and partially in detailapparatus connected and arranged in accordance with the present invention and capable of utilization in practicing the improved method disclosed herein.

Referring to the drawings, the apparatus there illustrated comprises .a plurality of, containing chambers Ill, ll, l2, [3,14, l5, l3, l1, l8 and I9 which, if the apparatus'is to beutilized in mixing lacquers,v for example, may comprise drums respectively containing the liquids identified by the names appearing thereon. These containing chambers are interconnected by a conduit system comprising feed pipes or conduits 20, 2|, 22', 23, 24, 25, .26, 21, 28 and 29 with a mixing chamber '30. More specifically, each of the enumerated conduits is connected to communicate with. a substantial U-shaped header 3| which is provided at suitable intervals along the legs thereof with T-joints for connection with the respective ends of the enumerated feed conduits. These conduits have included therein auxiliary control valves 20d, Zld, 22d, 23d, 2401, 2511, 26d, 21d, 28d and 29d, respectively, which areprovided in order to permit the disconnection of the feed conduits from empty containing drums-and the connection thereof tofilled drums while the apparatus .is being used. Normally, the enumerated auxiliary control valves are left open. The containing ,chambers H! to l9, inclusive,-may each comprise the usual liquid shipping drum; and each is provided with two openings through the top wall thereof, one of the openings being utilized for effecting a connection with the associated feed conduit and the other opening being provided for the purpose of venting the interior of. the drum to the surrounding atmosphere. To this end, inverted U-shaped conduits'32, 33, 34,35, 35, 31, 38, 39, 40 and 4| are provided which communicate respectively with-the drums 10,- l l,

l2, l3, l4, l5, l6. I7, I8 and id in the order named. Each of the enumerated U-shaped conduits terminates in a check valve which is directed to permit theadmission' of air to'tll' associated chamber andto prevent the escape of vaporization products or gases from the associated chamber. The manner of connecting the conduits 20 to 29, inclusive, and 32 to H, inclusive, with their respective associated drums is the same in each instance and, accordingly, will be readily understood from a consideration of the arrangement of the drum l9 illustrated in Fig. 3. This drum is provided with a cover plate 43 having two openings therein into which are sealed or fabricated internally threaded connection plugs 44 and 45, respectively. One section 25a of the conduit 25 is provided with an intake end disposed adjacent the bottom of the drum l9 and is threaded into a connecting thimble 45 which, in turn, is threaded into the plug 44. A second section 250 of the conduit 25 is threaded into the upper end of the thimble 46. The inverted U-shaped conduit. includes a section Ha which is threaded into a thimble 45a which, in turn, is threaded into the plug 45. The other end of the conduit H is connected to a check valve 41 of the movable ball type. More specifically; this valve comprises a body member He and a cap 412) having communicating openings 48a and 48b extending therethrough, which openings communicate with the interior of the drum l9 through the conduit 41. The upper end surface of the cap 411) is tapered downwardly to provide a seat for receiving a check ball 49, this ball normally being sealed in place over the opening 48b by the force of gravity to prevent vaporization products or gases generated within the drum 19 from escaping to the surrounding at mo'sphere'. It will be understood that when the pressure within the drum I9 is decreased below atmospheric pressure; the ball 45] is moved slightly to unblock the opening 482) and thus permit air to flow into the drum [9.

The drums ill to I9, inclusive, are supported by and. electrically connected to two metal plates 50 and which, preferably, rest upon the ground or are otherwise connected to ground by running conductors therefrom to a nearby water pipe.

These plates are supported and electrically connected to two metal posts 52 and 53, respectively, which form the supporting and electrical grounding structure for the feed pipes 20 to 29, inclusive. More particularly, the metal post 52 is provided with feet 52a which are anchored to the plate 50 by means of bolts or screws 52b. Similarly, thefeet 53a of the post 53 are anchored to the plate 5| by means of screws or bolts 531). For the purpose of securing the conduits 20 to 24, inclusive, to the upstanding metal post 52, five metal clamping brackets 54, 55, 56, 51 and 5B are provided which are bolted or otherwise secured to the post 52 and serve respectively to clamp the conduits 20 to 24, inclusive, to the post 52 in the order named. In a similar manner, the conduits 25, 26, 21, 28 and are clamped to the metal post 53 by means of five additional clamping brackets 59, 60, SI, 62 and 63, respectlvely.

In order to facilitate the interconnection of the conduits 20 to 29, inclusive, with the liquid containing drums ID to I9, inclusive, or with other other drums containing thesame or different liquids, these conduits are individually provided with flexible'sections 20b, 21b, 22b, 23b, 24b, 25b, 2517, 2112,2812 and 29!), each of which is identical in construction with the flexible conduit 251) shown in Fig. 3. More particularly, the flexible conduit 25b comprise a flexible metal liner 64, an intermediate layer of rubberous material and an outer covering 56 of fabric or flexible composition material. This flexible conduit section is connected at its upper end to the end of the adjacent section of the conduit 25 by means of a coupling connection which comprises mating members 51 and 68 and a split annular ring 69. The upper portion of the coupling member 57 is internally threaded to receive the threaded end of the adjacent section of the conduit 25 and is provided with a downwardly extending ledge 67a formed integral therewith and over which the upper end of the flexible conduit 25b is telescoped. In order to clamp the end walls of the flexible conduit 25b against this ledge the coupling member 61 is provided with an externally threaded annular portion 67b which is split longitudinally around its circumference, and the mating threads of this annular member and the other coupling member 68 are tapered. Accordingly, the several sections of the annular member 6112' compress the split ring 69 to seal the end side walls of the flexible conduit 25b against the ledge 51a as the two coupling members 61 and 68are screwed together. The lower end of the flexible conduit 25b is secured to the adjacent conduit section 250 by means of a similar coupling element '10 which includes a union joint H of conventional construction and arrangement. More specifically, the Coupling element 10 includes a body member 12, a split annular ring 13 and an annular compression member 14. The body member 12 is provided with an annular upstanding ledge 72a over which the lower end of the flexible conduit 2% is telescoped, and-with a second externally threaded upstanding member 1217 which is longitudinally split and cut away at points around its circumference to provide compression fingers. The member 121) is provided with tapered external threads which mate with the tapered internal threads of the compression member 14. As thus arranged, when the compression member 14 is screwed onto the annular member 12?), the split ring 13 is compressed to force the end side walls of the flexible conduit 25b against the ledge 12a and thus provide a gas-tight seal. From the foregoing explanation it will be apparent that the metal liner 64 which traverses the length of the flexible conduit 25b and at opposite ends thereof is compressed against the ledges 61a and 12a, provides an electrical connection between the coupling elements 6'! and 10 whereby the coupling element 10 is maintained at the same electrical potential, namely, ground potential, as the other parts of the apparatus. As a result, electrical discharges in the form of ignition sparks between the coupling element 10 and a liquid containing drum which may be moved into place on the supporting plate 51 for connection with the feed pipe 25 are positively prevented.

The common header 3| at which conduits 20 to 29, inclusive, terminate is connected to communicate with the mixing chamber or tank 33 through a connection I5 which has serially ineluded therein a vacuum pump 16 and a control valve 11. The vacuum pump 16' which is provided for the purpose of exhausting the header 3| to create a partial vacuum therein during op eration of the apparatus, is preferably of the meshing gear type and is arranged to be driven by a motor 18 through a speed reducing gear mechanism I9. In order selectivel to expose the conduits 20 to 29, inclusive, to the vacuum created in the header 3| through operation of the pump I6, thereby to permit the liquids contained in the drums ID to I53, inclusive, selectively to be withdrawn into the mixing chamber 38, the enumerated conduits are respectively provided with admission valves I9, 88, BI, 82, 83, 84, 85, 86, 8! and 88. These valves are preferably of the well-known gate type and are of identical construction. Briefly described, the valve 8i which is illustrated in detail, by way of example, comprises a body member 89 which is provided with oppositely disposed internally threaded portions into which th ends of the adjacent pipe sections are threaded. In the central portion of the body member 89 a' semi-annular shaped slot is formed to provide oppositely disposed valve seats arranged to receive therebetween a valve gate 90. This valve gate is mounted at one of its ends upon an operating spindle 9i which is journaled in a plug member 92. This plug member is threaded into an internally threaded opening drilled through the body mem ber 89 into the gate receiving slot and is provided with a small stufling box. This stuiling box is packed with sealing material and is threaded internally to receive the threaded end of a sealing cap 93 which is telescoped over the spindle 9|. The spindle 9| is provided at its free end with an operating handle 94 which is rigidly secured to the spindle 9| in any desired manner. This type of valve is particularlywell suited for use in the apparatus since it is easily and quickly operable between its fully opened and fully closed positions and permits of positive adjustment to a partially opened position where it will remain even though substantial pressures are exerted on the valve gate 90.

For the purpose of venting the common header 3| to the surrounding atmosphere, thereby positively to withdraw from the header any residue liquids or gases which maybe held therein following closure of one of the admission valves I9 to 88, inclusive, a vent valve 95, identical in construction with the valve 8|, is provided which is connected to the upper end of the left leg of the header. The other leg of the header 3i is connected to a vacuum gauge 96 Whichis provided for the purpose of measuring the decrease in pressure which occurs within the header during operation of the pump 16, thus providing an indication as to when this pressure has been sufficiently lowered to enable the liquids to be withdrawn from the containing chambers Hi to IS, inclusive.

In order to measure the liquids selectively withdrawn into the mixing chamber 36 from the containing chambers Ill to weighing apparatus comprising a set of platform scales 9'! is provided. More specifically, the mixing chamber 30 is supported upon the weighing platform of these scales and is arranged in the manner more fully described hereinafter for substantially free movement with the moving parts of the scales, whereby indications are given by the indicating element 97a of the scales 91 as to the quantity of each liquid discharged into the mixing chamber.

The liquids withdrawn into the mixing chamber 341 from the drums III to I9, inclusive, may selec tively be discharged into either of two agitating chambers 98 and 89. Alternatively, the contents of the mixing chamber 38 may be discharged di rectly into either of two storage drums or con- I9, inclusive,

tainers I M and HM, or through iilters'IM and I into either of .two additional storage drums or containers I02 and I03. To this end, two discharge pumps I06 and ID! are provided which are interconnected with the mixing chamber 30, the two agitating chambers 98 and 99, the storage drums Hill to I 03,'inclusive, and the filters I 04 and IE5 by means of a conduit system having suitable control valves provided therein. These pumps are arranged to be driven by motors I08 and I09, respectively, through suitable speed reducing gear mechanisms H0 and III, respectively. The filters I84 and IE5 are'preferably of the gravity flow discharge type and maybe of any desired commercial construction suitable for use in filtering viscous liquids. Each of these filters is provided with a tight fitting removable cover in order to facilitate removal of its filtering element for cleaning or replacement. I

The pump H31 in the arrangement illus trated, utilized solely to transmit liquids between the mixing chamber 39, the agitating chamber 98 and either of the two storage drums It!) and I82. To this end, the inlet side of the pump I II! is connected through a valve M2 to communicate with the mixing chamber 38 by way of an intake conduit H3 which conduit is also utilized to conduct liquids from the mixing chamber to the inlet side of the pump I05. The discharge end of the pump It! is connected by means of conduits H4 and 5 I5 having control valves lit and H1 respectively included therein, to communicate with the agitating chamber 98. A check valve I3! is also included in the conduit H4 in order to prevent any possibility of backward flow from the agitating chamber 98 after operation of the pump I81 is arrested. Theoutlet side or the pump I01 is also connected by way of a conduit IIS'having control valves H9 and I22 included therein to the intake side of the filter IM, a branch connection comprising a second control. valve I20 and a conduit I2I being utilized to connect the conduit H8 with the, storage drum Hill. The outlet side of the filter I84 is connected to communicate with the storage drum I82 through a conduit I23 which includes another control valve I24. In order to permit the contents of the .agi tating chamber 98 to'be returned to the mixing chamber 30 for the purpose of weighing the same, and to permit the contents of this agitating chamber to be discharged into one of the two storage drums I08 and I82, a conduit I25 is provided which communicates with the chamber 98 at the extreme bottom thereof and connects the interior of this chamber with the inlet side of the pump W1. A normally'closed control valve I26 is provided in this conduit in order normally to prevent the contents of the agitating chamber 98 from flowing back to the inlet side of the pump Ifi'l. Furtherto enable the pump lillto be utilized in discharging the contents of the agitating chamber 58 back into" the mixing chamber 30, the discharge end of this pump is connected over a path including the conduit I I4 and an additional '7 conduit I21 having a control valve mil-connected i therein to communicate with the interior of the mixing chamber. The pump Ill! may also be utilized for the purpose of; extracting samples from either the agitating chamber 98 or the mixing chamber 30. To this end, the discharge end of the pump ID! is also connected through a control valve I29 to a discharge pipe I30; In order to prevent excessive back pressures which may inadvertently be developed in the conduits -II4 and H8 from overloadingor stopping the pump I01, a. conduit I32 having a relief valve I33 connected therein is provided which connects the intake and discharge ends of the-pump. This relief valve is so connected and arranged and is so adjusted that under normal operating conditions it remains closed, but if the pressure developed on the outlet side of the pump exceeds a predetermined value it operates to provide a circulating path and thus relieve the load imposed upon the pump.

The conduit system interconnecting the mixing tank 30, the agitating chamber 99, the two storage drums I Ill and I03, the filter I05, and the pump I06 is identical in arrangement with that just described, which interconnects the mixing chamber 30, the pump I01, the agitating chamber 98, the filter I04 and the two storage containers I and I02. Briefly to describe this duplicate conduit system, the outlet side of the pump I06 is connected by means comprising conduits I34, I35, I35, I31 and I30 selectively to discharge liquids contained in the mixing chamber 30 into the agitating chamber 99, the storage container IIlI or through the filter I into the storage container I03; suitable valves I39, I45, I41, I42, I43 and I44 being provided for determining the direction of liquid flow. As indicated above. the common intake conduit I I3 is utilized for the purpose of conducting liquids to the inlet side of the pump I06, a control valve II2 being provided [or blocking liquid flow from the conduit II3 to the inlet side of the pump I01. To prevent back ward flow through the conduit I35 to the outlet side of the pump I06, a check valve I45 is provided in this conduit which is directed to permit flow into the agitating chamber 99 but to prevent backward flow from this chamber. For the purpose of conducting the contents of the mixing chamber 99 to the inlet side of the pump I05 there is provided a conduit I45 having a control valve I41 includedtherein. An additional conduit I49 having a control valve I50 included therein is provided which connects the outlet side of the pump I05 with the interior of the mixing chamber. In order to protect the pump I06 against excessive back pressures which may inadvertently be developed on the discharge side thereof a conduit I52, having a relief valve I5i therein is provided to connect the inlet and outlet sides of the pump I 06 so that a circulating path through this pump may be established in the event the valve I5I is opened. The discharge end of the pump I05 is also connected through a control valve I53 to a discharge I54, thereby to provide a path for withdrawing samples from the agitating chamber 99 or the mixing chamber 38.

In order to permit substantially free movement of the mixing tank or chamber 30 with the moving parts of the scales 91, gas-tight flexible con nectors of identical construction are utilized for sealing the openings through which the conduits 15, H3, I21 and I49 extend into the chamber 30. Thus, the section I43a of the conduit I49 extends through an enlarged opening provided in a plug I55 which, in turn, extends through an opening formed in the top wall or cover plate of the mixing chamber 30. This plug is fabricated or otherwise secured in sealed relationship to the sides of the opening formed in the cover of the mixing tank 30 through which it extends, and is provided with an upstanding annular ledge portion over which is telescoped the lower end of a flexible connector I56 formed of leather or non-porous composition material. The lower end of the flexible connector I55, after being telescoped over the end of the upstanding annular portion of the plug I is clamped in place by means ofa clamping strap I51 of conventional construction. The upper end of the flexible connector I56 is clamped to the outer surface of the pipe section I4Sa by means of a clamping strap I58. The other conduits II3, I21 and 15 include sections II3a, I21a and 15a, respectively, which are sealed to plugs inserted in the cover of the mixing tank 30 by means of flexible connectors I59, I and I10, respectively, of identical. construction and arrangement with the flexible connector just described. Each of the conduit sections II3a, I49a, 15a and I 2111 communicating with the interior of the mixing tank 30 includes a flattened end portion which extends within an annular well I'II formed in the bottom wall of the tank adjacent the side walls thereof. This well is provided for the purpose of enabling a liquid pool to be quickly formed within the mixing tank 30 thereby to minimize vaporization of the more volatile liquids required in mixing a batch of a desired product.

The agitating chambers 98 and 99 are of similar construction, the chamber 98 being illustrated, by way of example, as comprising inner and outer walls \vhichare spaced apart to define an annular heating chamber having a steam inlet conduit I12 communicating therewith. This conduit I12 may, if desired, be connected to any convenient source of steam. This arrangement permits ingredients introduced into the agitating chamber 98 to be readily heated, thereby to facilitate mixing. A removable cover plate I13 provided with a hinged portion I13a is utilized to close the top of the agitating chamber 98, the fixed portion of this cover plate being clamped tightly to the ends of the side walls of the chamber 98 in any suitable manner, and a latch mechanism, preferably of the toggle type, being provided for tightly clamping the hinged portion I13a, of the cover plate to the top edge of the chamber. Further to facilitate the mixing of ingredients deposited in or transmitted to the agitating chamber 98, an agitator or beater I14 is provided which is mounted upon a shaft I15 journaled in bearings extending through the side walls of the chamber and is arranged to be driven by a motor I16 through a speed reducing gear mechanism I11. The inner bottom Wall of the chamber is sloped downwardly toward the inlet end of the discharge conduit I25, thereby to insure complete drainage of the chamber when the discharge valve I25 is opened.

In order to facilitate the connection and disconnection of storage drums to the discharge conduits I2I, I23, I31 and I38, these conduits are provided with flexible sections I2Ia, I23a, I31a and I 58a each of which is identical in construction with the flexible conduit section 25b included in the conduit 25. Preferably, the storage drums used in this apparatus are identical in construction with the drum I92 which is illustrated in Fig. 3 of the drawings as includ ing a raised bottom portion which defines an annular liquid well I02a adjacent the side walls of the drum. The discharge conduit I23 is provided with a section I232) having a flattened discharge end which extends into this liquid well. The pipe section I23a is connected to a coupling plug I230 which is threaded into a mating plug member fabricated to the top wall of the drum I02. In order to prevent excessive back pressures from being developed in the discharge conduit I23, the pipe section I23b is provided with a small opening I23d which extends through the wall thereof at a point adjacent the inner sur-' face of the drum cover.

In order to withdraw from the mixing chamber 39, the two agitating chambers 98 and 99, and the four drums I to I03, inclusive, any vaporization products or gases resulting from the mixing and transmission of the volatile liquids utilized in the manufacture of products of the character described, exhaust apparatus is provided which includes a main exhaust conduit I18 having its outlet end communicating with the intake side of an exhaust fan I19. The discharge end of the fan I19 is connected to discharge vaporization products drawn into the conduit I18 on the outside of the building in which the mixing apparatus is housed. The conduit I19 is positioned above the two agitating chambers 98 and 99 and the mixing chamber and may, if desired, be supported from the ceiling of the housing structure by means of suitable suspension brackets. At suitably spaced points along its length, the main exhaust conduit I18 com-. municates with seven intake conduits I80, IBI, I82,

I83, I84, I85 and I86, each of which terminates.

in a downwardly extending inverted funnel shaped opening. More specifically, the enumerated intake conduits extend through openings provided in the side walls of the main exhaust conduit I18to communicate with the interior of the main conduit at points above the bottom thereof.

' These intake conduits are also arranged to communicate with vapor exhaust pipes I81, I88, I89, I90, I9I, I92 and I93, respectively, which extend to and communicate with the interiors of the storage drums I02, I00, the agitating chamber 98, the mixing chamber 39, the agitating chamber 99 and the storage drums IN and I03, re-

spectively. In order to insure adequate grounding of all parts of the exhaust apparatus, the main exhaust conduit I18 is electrically connected to a water pipe at one or more points along its length and good electrical connections are provided between all of the mechanically connected metal parts of this apparatus. The exhaust pipes I81, I88, I92 and I93 are provided with flexible sections I81a, I88a, I92a and I93av for facilitating the connection and disconnection of the associated drums to the main exhaust conduit I18. Preferably, each of these flexible exhaust pipe sections is identical in construction and arrangement with the flexible conduit section 2511 included in the conduit 25. The exhaust pipes I81 to I93, inclusive, are respectively provided with reversely bent funnel shaped end portions which are disposed within the funnel shaped openings of the respective associated conduits I80 to I88, inclusive. Thus, the exhaust pipe I81 terminates in an inverted funnel shaped end portion I812) which extends within the flared terminus of the conduit I80 and is positioned with its outer walls spaced apart from the inner walls of the flared terminus of the conduit I80. This pipe is supported from the conduit I80 by means of a bolt or rod I94 which passes through aligned openings provided in the inverted funnel shaped ends of the conduit I80 and the pipe I81, suitable provisions being made for preventing lateral displacement of the pipe I81 along the supporting element I98. The ex haust pipes I88, I89, I9I, I92 and I93 are similarly suspended from the flared ends of the intake conduits I8I, I82, I84, I85 and I86, respectively. The exhaust pipe I90 which communicates with the interior of the mixing chamber 30 is rigidly mounted upon the cover plate of this chamber for movement with the chamber and the moving parts of the scales 91. The inverted funnel shaped end of this exhaust pipe is disposed within the inverted funnel shaped opening forming one end of the conduit I83, the walls of these two funnel shaped openings being spaced apart so that no engagement occurs therebetween either when the chamber 30 is empty or when the chamber is filled with liquids withdrawn from the containing chambers I0 to I9, inclusive. In order partially to equalize the subatmospheric pressures developed within the various enumerated exhaust pipes through operation of the Venturi orifices thus formed between these pipes and their respective associated conduits I to I86, inelusive, the diameter of the main exhaust conduit I18 is decreased at one or more points along its length in the manner illustrated in the drawings.

In utilizing the apparatus briefly described above to manufacture lacquers, paints, enamels and the like the preferred practice is to provide. one shipping drum for receiving the mixed lacquer, paint or enamel and a separate drum for the thinner which is used by the consumer to prepare the raw lacquer, paint or enamel for use. If this apparatus is to be used in mixing a lacquer, for example, the chambers I0 to I9, inclusive, may respectively be utilized as containers for the liquids identified by the names respectively inscribed on these chambers. With the exception of toluol and damar solution all of these liquids are Well-known solvents commonly used in the manufacture of lacquers and lacquer thinners. Toluol is a well-known diluent and damar solution a well-known resinous body ingredient also commonly used in the manufacture of lacquers. Other body ingredients which may be used and which are obtainable either in solid, crystalline or paste form, are the ester gums, alkyd resins and phenolic resins. Thus, a typical formula which may be used in mixing a four hundred pound batch of lacquer is as follows:

Solvents Pounds Butyl acetate 64 Amyl acetlate 32. Ethyl acetate 16 Butyl alcohol 32 Butyl cellosolve 16 Diluent:

Toluol Lacquer base:

Nitrocellulose -10 Alkyd resin, phenolic resin, damar solution or the like 32 Dibutyl phthalate 8 To accompany the lacquer produced in accordance withthe above 'formula, approximately four hundred pounds of thinner therefor would ordinarily be required. A suitable formula for this thinner is as follows:

Pounds Butyl acetates. 80 Amyl acetate 40 Ethyl acetate; 20 Butyl alcohol 40! Butyl Cellosolve 20 Briefly to consider the method of mixing this lacquer and the thinner thereforin accordance with the above formulas the operator or attendant first initiates the operation of the motor-driven exhaust fan I19. With this fan operating, air is drawn through the orifices formed between the upstanding skirted ends of the exhaust pipes I81 to I93, inclusive, and the respective associated inverted funnel shaped ends of the intake conduits I80 to I86, inclusive, and

the main exhaust conduit I18, and is discharged.

is exerted on the upper end of the pipe I 90 which is sufficient to cause operation of the indicator 91a to a predetermined tare indication of zero pounds. After starting the exhaust fan I79 and observing the indication of the indicator 91a to see that the reading is correct, the operator next opens the valve I! and initiates operation ofv the motor I8 to drive the vacuum pump 16.- Through.

operation of this pump a partial vacuum is created in the U-shaped header 3'I.

When the pressure gauge 96 indicates that a predetermined subatmospheric pressure has been developed within the header 3|, the operator starts the mixing operation by opening one of the valves 19. to 88, inclusive, which is in.-

cluded in a conduit extending to a containing,

chamber having one of the desiredliquids therein. These valves corresponding to the desired liquids are operated one at a time to admit only one selected liquid to the mixing chamber 30 at a time and, preferably, the less volatile of the selected liquids are withdrawn into the mixing chamber 30 first. Thus, benzol and toluol, for example, are highly volatile liquids and tend to vaporize when subjected to the agitation which occurs incident to the transmission thereof to the mixing chamber. Accordingly, if one of these liquids were admitted to the mixing chamber first a large percentage thereof would be vaporized and withdrawn through the exhaust pipes I90 and I18 by the exhaust fan I19. On the other hand, amyl acetate is not-so volatile as the other liquids named. Assuming that the lastmentioned liquid is the one selected for initial admission to the mixing chamber 30, the valve 82 is operated to its open position, thereby to expose the conduit 23 and the interior of the containing chamber I3 to the partial vacuum created in the header 3I through operation of the pump "I6. When this valve is opened the amyl acetate contained in the chamber I3 is, by virtue of the atmospheric pressure exerted on the surface of the liquid through the check valve contained in the conduit 35, forced through the conduit 23, the base portion of the header 3i, the connection I and the pump 16 into the mixing chamber 30. As this liquid is initially discharged into the mixing chamber a pool is formed in the annular well III which quickly surrounds the discharge end of the conduit section 75a. The valve 82 is held open until approximately thirty-one pounds of the amyl acetate have been withdrawn into the mixing chamber 30 to produce a corresponding reading by the indicator 91a. As this reading is approached, the admission valve 82 is gradually closed to lessen. theliqu id how and is-fully closed Lin when the reading of thirty-one pounds is obtained. After fully closing this valve the attendant opens the vent valve 95, thereby to permit the residue liquid which is held in the header 3I and the section of the conduit 23 connecting this header with the valve 82 to be withdrawn through-the conduit I5 and the pump 15 into the mixing chamber 30. In practice, it has been found that approximately one pound of liquid will be withdrawn into the mixing chamber after an admission valve is fully closed. In this way the desired amount of thirty-two pounds of amyl acetate is accurately withdrawn into the mixing chamber 30. Before opening a second of the admission valves the vent valve is closed so that a partial vacuum is again created in the header 3| through operation of the pump 16.

If, following the withdrawal of the amyl acetate into the mixing chamber 35!, the butyl acetate, butyl cellosolve, ethyl acetate, butyl alcohol and toluol are withdrawn into the chamber in the order named, the admission valves 81, 88, 86, 81 and 84 are opened and closed one at a time. By an accumulative-weighing process the amount of each liquid as determined by the above formula may be accurately measured. Following the closure of each of these valves and before the next admission valve to be operated is opened, the vent valve 95 is operated for the purpose of withdrawing any residue liquid held in the header 3| and the one of the associated conduit sections which extends to the last operated admission valve.

From the foregoing explanation it will be apparent that each of the liquids discharged into the mixing chamber after the amyl acetate is introduced therein is discharged beneath the surface of the liquid pool formed in the well III. As these liquids are transmitted from their respective containing chambers to the mixing chamber 30 they tend to vaporize, but the resulting vapors, upon entering the liquid pool are by'condensation reconverted into liquids. Accordingly, the exhaust apparatus is prevented from withdrawing a substantial portion of the volatile liquids while in a vaporous state. A substantial reduction in the quantity of liquids wasted during the mixing thereof is thus effected. Further, by discharging the liquids into the mixing chamber beneath the surface of the liquid pool formed in the well ITI the intermixture thereof is enhanced.

After the thinner for the lacquer has been measured and mixed in the mixing chamber 3!! in the manner just explained, it may be transmitted to the agitating chamber 98, for example, for mixing with the base or body substance of, the lacquer. To this end, the motor IDS is started to initiate operation of the pump IN; the valves I26, I28, II9, I29 and I48 are closed; and the valves H2, H6 and II! are opened. After the enumerated control valves have been operated in themanner indicated and the motor I09 has been started, the pump IUI operates to transmit the-mixed liquids contained in the mixing-chamber 30 to the agitating chamber -98 over a liquid flow path which comprises the-common discharge conduit II 3, the valve H2, the pump I01, the

conduit I I4, the valve H6, the conduit H5 and the'valve I I1. Initially, only a small portion of the batch of the mixed liquids contained in the mixing chamber 30 is admitted to the agitating chamber 98, the valves H2 and II I being closed temporarily to arrest the liquid transmission after the desired quantity of liquid is discharged into this agitating chamber. After these valves are closed the cover door I13a is opened and the base or body substance of the lacquer, which may be in solid, crystalline or paste form, is deposited in the agitating chamber 98. This body substance may, as was pointed out above, consist of forty pounds of nitro-cellulose, thirty-two pounds of an alkyd or phenolic resin, and eight pounds of dibutyl phthalate. After the base or body substance of. the lacquer is thus introduced into the agitating chamber 98, the door I13a is closed and latched and the motor I16 is started to initiate operation of the agitator I14, thereby to intermix the lacquer base with the liquid mixture which has been previously conducted to the agitating chamber.

As agitation of the mixture contained in the chamber 08 progresses the valves II 1 and H2 may again be opened for the purpose of discharging the remaining contents of the mixing chamber into the agitating chamber 98. If desired, these valves may be opened and closed intermittently in order to admit only a small portion of the liquid mixture tothe agitating chamber as themixing of the liquids with the lacquer base progresses.

a After all of the liquid mixture contained in the mixing chamber 30 is withdrawn into the agitating chamber 98, the mixing chamber may beutilized for the purpose of mixing the four hundred pound batch of thinner which is to be used with the lacquer which is in the process of being manufactured. To this end, the admission valves 82, BI, 88, 88, 81 and 84 are again operated one at a time and in the order named for the purpose of withdrawing the above-described liquids of the thinner into the mixing chamber. As each liquid is withdrawn into the chamber 30 it is measured through operation, of the scales 91. Also, following the withdrawal of the desired quantity of each liquid and the closure of the admission valve corresponding thereto, the vent valve 95 is opened for the purpose of withdrawing into the mixing chamber the residue of the liquid contained in the header 3| and the associated last used conduit section.

After the liquids of the thinner are intermixed in the mixing chamber 30, they may be pumped directly into the storage drum I90. To this end, the control valvesI48, I26, H6, I25 and I22 are held closed and the control valves H2, H8 and I20 are opened. Thus, the contents of the mixing chamber 80 are discharged into the storage drum I08 over a liquid circuit which includes the conduit M3, the valve II 2, the pump I91, the valve H9, the conduit H8, the valve I20 and the conduit I2i. After the drum I00 is filled the valveltt may be closed and the flexible section I2I a of the conduit I2I disconnected from the connecting plug provided in the top of the drum I00. A sealing plug is now inserted in the connecting plug. In addition, the flexible section I88aof the exhaust pipe I88 is disconnected from the other connecting plug provided in'the drum I06 and a sealing pluginserted in this connecting plug. These operations may all be carried out'whilc the lacquer is being mixed in the agitating chamber 98. After the ingredients of the lacquer are thoroughly intermixed in this chamber they may, through operation of the pump I01; be discharged through the filter I04 into the storage drum I02 orconducted back to the mixing chamber to be reweighed; Assuming that the lacquer is to be discharged directly into the storage drum I02 through the valve I24 and the conduit I23. By virtue of the annular well I02a provided in the storage drum I02 a liquid pool is quickly formed in the bottom of this drum so that the major portion of the filtered lacquer is introduced into the drum beneath the surface of the pool. As a result, the vaporization products resulting from the mixing, transmission and fil-' tration of the lacquer are for the most part condensed in the liquid pool so that only a small portion thereof are Withdrawn through the exhaust pipe I81 into the exhaust conduit I18. In practice it was found that in filling the storage drums in the manner just explained substantial back pressures were developed in the ,dis-

i charge conduit sections connected to the drums.

Such back pressures were probably occasioned by excessive vaporization of the volatile constituents of the lacquer thinner during the transmission of the liquid over the fiow path in use, which occurred with such rapidity that the rate of dis charge dld not compensate for the expansion of the gases. Regardless of the cause, it was found that the pressures developed were in some cases of sufiicient magnitude to either stop the pump I01 from operating or to cause operation of the relief valve I33. In certain instances, the back pressures developed were of suificient magnitude that the top of the filter I04 was blown off, thus dis; charging the vapors contained in the filter into the surrounding atmosphere. In order to obviate this difficulty the small openin I23d was pro-- vided in the discharge conduit section I231) for the purpose of relieving the pressures developed when discharging liquids through the filter I04. After this expedient was resorted to no further difiioultyfwas experienced, the, filling of storage drums connec'tedtothe conduit I23 proceeding in the, desired manner. was found advisable. to provide small venting openings in the discharge sections of the conduits I2I, I31 and I38, these openings being arranged identically with the opening I23d provided in the wall of the discharge conduit section If it is desired to conduct the lacquer mixed in the agitating chamber 98 back to the mixing chamber 30 for the purpose of reweighing the same prior to transmission thereof to the storage drum I02, the valves II2, I29, H9 and H1 are maintained closed and the valves I 26, I Hi and I28 are opened. As a result, a flow path is estab lished which extends from the bottom of'the agitating chamber 98 through the valve I25, the conduit I25, the pump I01, the conduit H4, the valves H6, I3I and I28 and the conduit I21 to the annular well I1I formed in the bottom of the mixing chamber 30. thus transmitted from the agitating chamber 98 back to the mixing chamber 30 the operator may, of course, observe the weight thereof and then discharge the lacquer into the storage drum I02.

To this end, the valves I48, I20, I25, 6 and I29 are either closed or left closed and the valves I I2;

From the filter I04 the filtered products are by gravityfiow conducted to the For the same purpose itv After the lacquer has been mixing chamber 30 by wayof the conduit H3, the valve H2, the pump IN, the valve H9, the conduit l 58, the valve I22, the filter I04, the valve I24 and the conduit I23 to the storage drum I02.

It will be understood that during the mixing of the lacquer and the thinner therefor in the manner just described, the exhaust .fan I79 is continuously operated for the purpose of withdrawing the vaporization products which are produced incident to the mixing and transmission f the volatile liquids and which. collect above the surfaces of the liquid pools respectively formed in the mixing chamber 30, the agitating chamber 90 and the two storage drums I and I02. These vaporization products are, as explained above, discharged by the fan I19 externally of the building housing the mixing apparatus. In this regard it will be noted that the exhaust apparatus is arranged to preclude any possibility of residue gases contained in the main exhaust conduit I18 from leaking back through the intake conduits I80 to I88, inclusive, into the interior of the housing structure after operation of the exhaust fan I19 is arrested. It is for this purpose that the intake conduits I80 to I86, inclusive, are connected to communicate with the main exhaust conduit I18 along the side wall of this main conduit and at points displaced above the bottom thereof. More specifically, the vaporization products which occur incident to the mixing and transmission of liquids of the character described are heavier than air and so that when released in air they move down instead of up. Accordingly, the residue gases-contained in the main exhaust conduit I'I8 after operation of the fan H9 is arrested are moved to the bottom of this conduit and cannot leak back through the intake conduits I80 to I93, inclusive, into the atmosphere surrounding the apparatus.

If the operator desires, he may after mixing the thinner for the lacquer and discharging the same into the storage drum I00 in the manner just explained, utilize the mixing chamber 30 and the agitating chamber 99 for the purpose of mixing a second batch of lacquer and a batch of thinner therefor to be discharged into the other two storage drums I03 and IN, respectively, all while the first batch of lacquer is being mixed in the agitating chamber 98. In such case, the valves I28 and I I2 are preferably held closed while the liquid constituents of the second batch of lacquer are being withdrawn from the proper containing chambers I0 to I9, inclusive, into the mixing chamber 30. After the liquid constituents of the second batch of lacquers are thus mixed they may be discharged into the agitating chamber 99 over a liquid flow path which comprises the conduit H3, the valve I48, the pump I00, the conduit I35,- the valves I39 and I45, the conduit I36 and the valve I4 I. While the second batch of liquid mixture is being intermixed with the base or body substance of the lacquer in the agitating chamber 99, the second batch of thinner may be mixed in the chamber 30 by withdrawing the desired liquids from the storage containers I0 to I9, inclusive. After the second batch of thinner is thus mixed it may be withdrawn from the mixing chamber 30 and discharged into the storage drum I M through operation of the .pump I06 over a liquid flow path including the discharge conduit II3, the valve, I48, the pump I06, the valve I40, the conduit I34, the valve I42 and the conduit I31. After the secondbatchcof thinner is thus discharged, into :the storage drum I II I either of the two batches of lacquerinzthe process aofibeing mixed in the-two chambers .98 and .99 :may be withdrawn first and either discharged-into the mixingchamher 30 for reweighing or conducted directly to the drum which has beenzprovided for its storage. Assuming-that the lacquer mixed in the agitating chamber 99 is to be filtered and then discharged into the storage drum I03, suitable valve operations, apparent from the preceding explanation, are made .to establish a liquid :fiow pathwhichextends from the-bottom ofzthe chamber 99 by way of the valve I41, the conduit I46,

the pump I08, the valve I40, the conduit I34, the valve I43, the filter I05, the valve I44 and the conduit I38 to the drum I03. If the lacquer mixed in the agitating chamber 99 is to .be reweighed prior to storage in the drum I03, the control valves are operated to establishxa flow path which extends by way-of the valve 1.4.7, the conduit I46, the pump I06, the conduit I35, the valves I39 and I 45, the valve I50'and theconduit I49 .to the interior of the mixing chamber 30. From the mixin chamber the reweighed lacquer maybe discharged through the filter I05 into the storage drum I03 over a flow path which includes the common discharge conduit I I3, the valve I48, the pump I06, the valve I40, the conduit I34, the valve I43, the filter I05, the valve I44 and the conduit I38.

The damar solution which -is contained in the chamber I4-constitutes alacquer body substance which consists of a resin in solution with liquids which include a small percentage of liquid wax. If this solution is'to be used as the body substance of a particular batch of lacquer, the desired amount of the solution is withdrawn into the mixing chamber 30 for measurement and is then discharged into a selected one of the agitating chambers 98 and 99 before the desired solvents and diluents of the lacquer are withdrawn from those of the containing chambers I0 to I9, inclusive, in which they are contained into the mixing chamber 30 for mixing. Aft-er mixture-in this chamber these intermixed liquids are, of course, transmitted to the selected one-0f the agitating chambers for mixture with the 'damar solution, after which the mixed lacquer may be handled in the manner described above.

The arrangement of the apparatus is such that if the operator desires or finds it necessary, the pump I06 may be utilized for the purpose of discharging the contents of the agitating chamber 98 into the storage drum I03. To this end, the control valves are operated to establish a liquid fiow'path which extends from the bottom of the chamber 98 by way of the valve I26, the conduit I25, the valves H2 and I48, the pump I06, the valve I40, the conduit I34, the valve I43, the filter I05, the valve I44 and the conduit I38 into the drum I03. Similarly, a liquid flow path may be established wherein the pump I0! is utilized to transmit the contents of the agitating chamber 98 to the storage drum 99. In this casethe control valves are operated to establish a liquid flow path which extends from the bottom of the agitating chamber 99 by way of the valve 141, the conduit I46, the valves I48 and H2, the pump I01, the valve II9, the conduit I I8, the valve I22, the filter I04, the valve I24 and the conduit I23 into the drum I 02. By providing a control valve in the common discharge conduit I I3 each of the two pumps I06 and I 01 may also be utilized to transmit liquids from either of the two agitating chambers 98 and '99 to the mixing chamber 30,

From the foregoing explanation it will be apparent that the apparatus is arranged to obtain themaximum flexibility of operation in the mixing of different batches of lacquer, paints, enamelsand the like, and of thinners therefor. In this connection it will be apparent that, if desired, the portion of the mixing apparatus which comprises the agitating chamber 99, the pump I 06 and its associated driving equipment and the conduit system interconnecting these mixing units with the mixing chamber 30 and the .main exhaust conduit I18, may be omitted. In such case, the unused opening of the T-joint which connects the common discharge conduit II3 with the valve I48 may be plugged or an elbow joint connecting the conduit II3 directly with the valve II2 substituted for the T-joint.

From the preceding explanation of the operation of the system it will be apparent that by suitable valve operations either of the two pumps I05 and I0! may be utilized for the purpose of withdrawing a sample from the mixing chamber 39 or either of the two agitating chambers into an open container. Thus, if the pump I06 is used for withdrawing a sample from the mixing chamber 30, for example, the Valves II2, I39, I41 and Hill are closed and the valves I48 and I53 are opened so that a flow path is established whereby liquids in the mixing chamber may be discharged through the outlet I54 into the container. Alternatively, if the pump I0! is utilized for this purpose the valves I48, H6, I36 and H9 are closed and the valves I I2 and I29 are opened so that the liquids may be discharged through the outlet I30 into the container.

Although the apparatus and method described above are of particular utility in the mixing of lacquers, paints and the like, in that all operations may be accurately and rapidly carried out by one operator and the fire hazard attendant with these operations is completely eliminated, itwill be understood that they are also of utility in the production of liquors and other products which involve the intermixture of volatile and inflammable liquids.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein, and

it is contemplated to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. In apparatus for mixing a plurality of different liquids at least a portion of which are volatile and which comprises separate containing chambers for said liquids, a mixing tank, conduits for conducting the liquids in said containing chambers to said mixing tank, means for selectively exhausting said conduits one at a time, thereby to withdraw one at a time selected liquids from said containing chambers into said mixing tank, and weighing apparatus comprising a movable part supporting said mixing tank and operative to measure the quantity of each liquid transmitted to said mixing tank; the combination which includes an exhaust fan for with-' drawing from said mixing tank any vaporization products resulting from the transmission and mixing of said volatile liquids, and conduit means connecting the interior of said mixing tank with said exhaust fan and provided with a pair of relatively movable orifice members arranged to permit substantially free movement of said mixing tank with said movable part of said weighing apparatus. p g

2. In apparatus for mixing a plurality of different liquids at least a portion of which are volatile and which comprises separate containing chambers for said liquids, a mixing tank, conduits for conducting the liquids in said containing chambers to said mixing tank, means for selectively exhausting said conduits one at a time, thereby to withdraw one at a time selected liquids from said containing chambers into said mixing tank, and weighing apparatus provided with a movable part supporting said mixing tank and operative to measure the quantity of each liquid transmitted to said mixing tank; the combination which includes an exhaust fan for withdrawing from' said mixing tank any vaporization products resulting from the transmission and mixing of said volatile liquids, an exhaust conduit extending to said fan and disposed above said mixing tank, an intake conduit communicating with one of the side wall portions of said exhaust conduit and terminating in a downwardly extending flared opening, and another conduit communicating with the interior of said mixing tank and including a portion terminating in an exhaust opening nested within but displaced from the inner side walls of said flared opening to permit substantially free movement of said mixing tank with said movable part of said weighing apparatus. V

, 3. In apparatus for mixing aplurality of different liquids at least a portion of which are volatile and which comprises a mixing tank, closed liquid transmission apparatus including means selectively operable to discharge selected ones of said liquids into said mixing tank one at a time, and weighing apparatus provided with a movable part supporting said tank and operative to measure the quantity of each liquid transmitted to said tank; the combination which includes. an exhaust fan for withdrawing from said tank any vaporization products resulting from the transmission and mixing of said liquids, an exhaust conduit extending to said fan and disposed above said mixing tank, an intake conduit communicating with one of the side wall portions of said exhaust conduit and terminating in a downwardly extending flared opening, and another conduit communicating with the interior of said mixing tank and including a portion terminating in an exhaust opening nested within but displaced from the inner side walls of said flared opening to permit substantially free movement of said mixing tank with said movable part of said weighing apparatus. I I

4. Apparatus for mixing a plurality of difierent liquids atleast a portion of which are vola tile comprising separate containing chambers for said liquids, a mixing chamber, a common header connected to said mixing chamber, conduits individually connecting said containing chambers with said common header, means for creating a vacuum in said header, valves included in said conduits and selectively operable to expose the associated conduits to the vacuum in said header, thereby to withdraw selected liquids from said containing chambers into said mixing chamber, and means for venting said header to atmos phere, thereby to permit liquids held insaid header after closure ofsaid valves to be drawn intojsaid mixing chamber; 7 j V V 5. Apparatus-,for mixing a plurality. of different liquids at least a portion; of; which are volatile with a paste, solid or powder material comprising separate containing chambers for said liquids, a first mixing chamber, conduits for conducting the liquids in said containing chambers to said mixing chamber, means for selectively exhausting said conduits, thereby to withdraw selected liquids from said containing chambers into said mixing chamber, a second mixing chamber including provisions for depositing said paste, solid or powder material therein, a pair of storage containers, a filter, conduits interconnecting said mixing chambers, said storage containers and said filter, and means comprising a pump in cluded in one of said conduits for selectively discharging the contents of said first mixing chamber into said second mixing chamber or into one of said storage containers over a path including said filter or into the other of said storage containers over a path from which said filter is excluded. 1

6. Apparatus for mixing a plurality of different liquids at least a portion of which are volatile with a paste, solid or powder material comprising separate containing chambers for said liquids, a first mixing chamber, conduits for conducting the liquids in said containing chambers to said mixing chamber, means for selectively exhausting said conduits, thereby to withdraw selected liquids from said containing chambers into said mixing chamber, a second mixing chamber including provisions for depositing said paste, solid 0 or powder material therein, a pair of storage containers, a filter, conduits interconnecting said mixing chambers, said storage containers and said filter, means comprising a pump included in one of said conduits for selectively discharging the contents of said first mixing chamber into said second mixing chamber or into one of said containers over a path from which said filter is excluded, and means including said pump for selectively discharging the contents of said second mixing chamber into said first mixing chamber or into the other of said containers over a path including said filter.

'7. Apparatus for mixing a plurality of liquids at least a portion of which are volatile comprising separate containing chambers for said liquids, a mixing tank having a depression in the bottom thereof, an inlet conduit extending into said mixing tank and having a discharge end disposed in said depression, conduits extending to said containing chambers and connected to said inlet conduit, and means for selectively exhausting said last-named conduits, thereby to transmit selected liquids from said containing chambers through said inlet conduit into said mixing tank.

8. Apparatus for mixing a plurality of liquids at least a portion of which are volatile comprising separate containing chambers for said liquids, a mixing tank, conduits connecting said containing chambers with said mixing chamber, means including said conduits for selectively transmitting liquids from said containing chambers to said mixing chamber, a storage container including a bottom wall having a depression therein, an inlet pipe extending into said container and terminating in a discharge end disposed in said depression, a filter, and means for transmitting liquids from said mixing chamber through'said filter and said inlet pipe into said container.

9. Apparatus for mixing a plurality of liquids at least a portion of which are volatile comprising separate containing chambers for said liquids, a mixing tank, conduits connecting said containing chambers with said mixing chamber, means in cluding said conduits for selectively transmitting liquids from said containing chambers to said mixing chamber, a storage container including a bottom wall having a depression therein, an inlet pipe extending into said container and terminating in a discharge end disposed in said depression, said inlet pipe having an opening extending through the wall thereof at a point within and adjacent the top of said container to relieve back pressures developed in said pipe, a filter, and means for transmitting liquids from said mixing chamber through said filter and said inlet pipe into said container.

10. In combination with a storage container for receiving a liquid mixture including volatile constituents and provided with a bottom wall having a depression therein, an inlet pipe for discharging said mixture into said container and provided with an opening extending through the wall thereof at a point adjacent the top of said container to relieve back pressures developed in said pipe, apparatus for mixing the constituents of said mixture, and means for transmitting said mixture from said apparatus through said inlet pipe to said container.

11. The process of preparing a predetermined blended liquid from different liquids at least a portion of which are volatile, which comprises withdrawing selected ones of said liquids one at a time from their sources into a mixing zone, accumulatively weighing the liquids thus withdrawn into said mixing zone, and exhausting said mixing zone to maintain a subatmospheric pressure therein continuously during the withdrawal of said liquids into said zone.

12. The process of preparing a predetermined blended liquid from difierent liquids at least a portion of which are volatile, which comprises exhausting a mixing zone to create a sub-atmospheric pressure'therein, withdrawing a selected one of said liquids of lesser volatility from its source into said mixing zone to form a vapor condensing pool in thebottom of said mixing zone, withdrawing other selected liquids from their sources, discharging said other selected liquids into said mixing zone beneath the surface of said pool, and measuring the quantity of each liquid thus withdrawn into said mixing zone.

13. The process of preparing a predetermined blended liquid from diiierent liquids at least a portion of which are volatile, which comprises exhausting a common chamber or header and a common mixing zone to create a sub-atmospheric pressure therein, sucking selected ones of said liquids from their sources through said common chamber into said mixing zone during succeeding and non-overlapping intervals, venting said common chamber to the atmosphere between at least a portion of said intervals, and measuring each liquid thus withdrawn into said mixing zone.

14. The process of preparing a predetermined blended liquid from difierent liquids at least a portion of which are volatile, which comprises withdrawing selected ones of said liquids from F their sources one at a time into a mixing zone,

accumulatively weighing the selected liquids as they are withdrawn into said mixing zone, and exhausting said mixing zone to produce a predetermined tare indication of the weighing apparatus before the selected liquids are withdrawn into said mixing zone.

15. The process of preparing a predetermined blended liquid from difierent liquids at least a portion of which are volatile, which comprises withdrawing a selected one of said liquids of lesser volatility from its source into said mixing zone to form a vapor condensing pool in the bottom of said mixing zone, withdrawing other selected liquids from their sources one at a time, discharging said other selected liquids into said mixing zone beneath the surface of said pool, accumulatively weighing the selected liquids as they are withdrawn into said mixing zone, and exhausting said mixing zone to produce a predetermined tare indication of the weighing apparatus before the selected liquids are withdrawn into said mixing zone.

16. The process of preparing a predetermined blended liquid from different liquids at least a portion of which are volatile, which comprises exhausting a common chamber or header to create a sub-atmospheric pressure therein, sucking a selected one of said liquids of lesser volatility from its source through said common chamber into a mixing zone to form a vapor condensing pool in the bottom of said mixing zone, sucking other selected liquids from their sources into said common chamber during succeeding and non-overlapping intervals, discharging said other selected liquids from said common header into said mixing zone beneath the surface of said pool, and venting said common chamber to atmosphere between at least a portion of said intervals.

17. lhe process of preparing a predetermined blended liquid from different liquids at least a portion of which are volatile, which comprises exhausting a common chamber or header to create -a sub-atmospheric pressure therein, sucking a selected one of said liquids of lesser volatility from its source through said common chamber into a mixing zone to form a vapor condensing pool in the bottom of said mixing zone, sucking other selected liquids from their sources into said common chamber during succeeding and non-overlapping intervals, discharging said other selected liquids from said common chamber into said mixing zone beneath the surface of said pool, venting said common chamber to atmosphere between at least a portion of said intervals, accumulatively weighing the selected liquids as they are discharged into said mixing zone, and exhausting said mixing zone to produce a predetermined tare indication of the weighing apparatus before the selected liquids are discharged into said mixing zone.

18. In apparatus for mixing a plurality of different liquids at least a portion of which are volatile and which comprises a'mixing tank, closed liquid transmission apparatus including means selectively operable to discharge selected ones of said liquids into said mixing tank one at a time, weighing apparatus provided with a movable part supporting said tank and operative to measure the quantity of each liquid transmitted to said tank; the combination which includes an exhaust fan for withdrawing from said mixing tank any vaporization products resulting from the transmission and mixing of said volatile liquids, and a connection between the interior of said mixing tank and said exhaust fan, said connection including a pair of relatively movable conduits separated to define an air intake orifice.

19. Apparatus for mixing a plurality of liquids at least a portion of which are volatile comprising separate containing chambers for said liquids, a mixing tank having a depression in the bottom thereof, an inlet conduit extending into said mixing tank and having a discharge end disposed in said depression, conduits extending to said containing chambers and connected to said inlet conduit, and means comprising valves included in said last-named conduits for transmitting selected liquids from said containing chambers through said last-named conduits and said inlet conduit into said mixing tank.

A. DE VERE BARNETT. 

